Communication units located at and functioning with a security gate entry system are well known in the art. Typically, these units are located adjacent to a moveable barrier or gate located at an entryway into an apartment complex or gated community. A person arriving at the entry will typically look up the number of the unit of the person they want to see on a display screen and then call that unit located within the complex on the security system telephone or similar communication apparatus located at the entryway. Once the person in the unit answers they can authorize opening of the gate to allow entry into the complex. Over the years these systems have become more sophisticated in what they can do. U.S. Pat. No. 5,854,831, for an Access Control Apparatus For Use With Buildings, Gated Properties And Their Like, owned by the assignee herein and incorporated herein by reference shows and describes a fairly sophisticated version of a telephone entry unit.
The unit described in the '831 patent includes a visual display and memory for holding information on the various occupants of units within the area to which access is restricted. This information often has to be updated as occupants move in and out. In the unit shown in the '831 patent includes an internal RAM memory, or other appropriate memory, to hold this information or it can be contained in PCMIA cards that fit into the top slot as depicted therein. Telephone entry units can also connect to and control functional parts of the gate opening systems. The units themselves can connect to the units of occupants within the restricted access area by a private communication line. In another variation the phone entry unit can actually connect into the public telephone system and when a person at the communication unit dials a code for a particular unit the telephone entry system will actually dial the telephone number of the unit being called.
Many of these communication entry units include dedicated computer systems that provide a variety of functions including diagnostic systems in additional to the standard occupant directories. In order to make the unit fully functional, electronic communication access ports have to be provided for a variety of situations. Among them are connectability to public telephone lines, to a hand held diagnostic unit or computer of a technician servicing the communication unit, and to a central control unit over a private communication line. To provide this functionality it has been necessary to provide a variety of different types of communication ports including a serial port, parallel port, RS 232 port and standard modular telephone jack. The unit described and depicted in the '831 patent includes most of these ports as well as a PCMCIA slot. All of these connections need there own circuitry as well as passive and active electronic parts including various computer chips in order to function properly. Thus, these communication units can have fairly sophisticated and redundant communication connections. These redundant features not only add significantly to cost and manufacturing complexity but also create a greater possibility of failure or malfunctioning of the unit.
Thus, there is there is a need to eliminate the excess redundancy in the circuitry of a communication entry unit while not sacrificing the connectability and functionality of these units.